[xsl] xslt 2.0 castable as

[David.Pawson@xxxxxxxxxxx]

I have a few strings of this nature

<ientry2>unit: see unit abbreviations</ientry2>
<ientry1>alphabets,  non-Roman, 5.7, 7.5.10, Appendix I</ientry1>
<ientry1>at, commercial sign for, 2.6, 7.2.8-10</ientry1>

which are index contents.

I'm trying to separate the term from the targets,
and using castable as to test for the 'first' numeric term, if there is one.

process is

tokenize the string

then test 
  if (. castable as xs:float)

I *thought* this would return true if the value, when cast,
returned a valid float.
e.g.  2.6 returns true, non-Roman returns false. Seems sensible.

spec says:

XPath provides a form of Boolean expression that tests whether a given value
is castable into a given target type. 

Note the phrasing, 'value', not type. Saxon seems to be telling me
that xs:string is castable as a float.

I found, saxon 7.8, that ('non-roman' castable as xs:float) returns true.

I then tried if (xs:float('non-roman')) which,
though getting ridiculous, actually returns what I want.

Is my logic right, or flawed please?


Regards DaveP.

**** snip here *****

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